SiC (silicon carbide) is expected to be a material for next-generation semiconductor devices. SiC has excellent physical properties, having a band gap three times wider than that of Si (silicon), a breakdown field strength approximately 10 times higher than that of Si, and a heat conductivity approximately three times higher than that of Si. A semiconductor device that has low loss and is capable of high-temperature operation can be realized by taking advantage of those properties.
In a case where a MIS (Metal Insulator Semiconductor) structure is formed with SiC, however, the density of interface states or the like existing between the semiconductor and the insulating film is higher than that of Si. Therefore, the charge mobility becomes lower, and the on-state resistance of a MISFET (Metal Insulator Semiconductor Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor) becomes higher.